This invention relates to devices for guiding a PC card or the like into a card slot, and more particularly to a card guide providing tactile feedback of improper Pc card orientation.
The Personal computer Memory card International Association (PCMCIA) is a group of manufacturers and vendors formed to promote a common standard for personal computer-based peripherals, primarily on laptop, palmtop, and other portable computing devices. A Pc card is an add-in card that conforms to the PCMCIA specification. The Pc card is a removable device approximately the same size as a credit card (54 mm.times.85.6 mm) designed to plug into a PC connector. Release 1 of the PCMCIA specification, introduced in September 1990, specified a Type I card that is 3.3 mm thick. Type I cards are primarily memory-related peripherals, such as RAM, ROM, EEPROM, and flash memory. Other peripherals such as sound cards are also available as a Type I PC card. Release 2 of the PCMCIA specification, introduced in September 1991, specified a Type II card that is 5.0 mm thick, and a Type III card that is 10.5 mm thick. Type II cards accommodate devices such as a modem, fax, network interface, or sound card. Type III cards accommodate devices that require more space, such as a wireless communications device or a rotating storage media (e.g., hard disk). A revision of the PcMcIA standard is under consideration for a PC card 32, that may include support for a 32-bit bus interface, multifunction cards, and power management.
A conventional PC card includes a female connector which couples to a 68-pin male connector inside a PC slot. The male and female connectors are the same for Type I, Type II and Type III PC cards. Because, the card heights vary among types, however, Type I, Type II and Type III slots differ. In particular, the slot widths are the same but the slot heights differ. Typically, a Type I slot can accommodate only a Type I PC card. Typically, a Type II slot can accommodate only a Type II or a Type I PC card. A Type III slot can accommodate a Type III, Type II or a Type I PC card.
Because there are 68 PC card openings to be aligned with 68 PC connector pins, proper card orientation is needed during insertion. To align the card properly, grooves defined at the edges of the card and ridges defined at ends of the male connector form a keying structure. If, for example, the card is inserted upside down, then the grooves and ridges do not align preventing mating of the card openings and connector pins. An improper orientation can lead to improper connection and the potential for damaging the PC card or host device circuitry. Users may even try to force a card in a manner that damages the card, the connector pins or the card slot. Accordingly, there is a need for the installer to be able to detect when a PC card is improperly oriented.
Existing devices for signifying proper orientation of a PC card during insertion are categorized as electronic sensing devices or mechanical insertion prevention devices. In addition, magnetic sensing devices are useful for cards with a recorded stripe, (e.g., ATM card). Electronic and magnetic sensing devices typically determine whether a card is properly oriented only after the card is inserted fully within the slot out of the installer's grasp. Specifically, the sensing devices become active once the card is substantially inserted. Also, the circuitry for the sensing devices is relatively expensive and costly to manufacture. Further, electronic and magnetic sensing devices require that electrical power be available during the sensing operations. The expense, lack of immediate feedback, and power requirement are undesirable features. Accordingly, there is a need for less expensive, powerless devices providing immediate orientation feedback.
Mechanical insertion prevention devices typically are less costly than the electronic and mechanical sensor counterparts, and do not require power. The known mechanical devices, however, do not provide unequivocal, immediate, tactile or visible feedback of improper orientation. In slots in which the card is completely contained, ejection mechanisms are necessary, otherwise removal of the improperly oriented card is difficult. In slots in which a portion of the card protrudes during operation, the difference in position between a properly oriented card and an improperly oriented card is too small to clearly indicate that the card is improperly oriented. Accordingly, there still is a need for an inexpensive mechanical device providing immediate tactile and visible feedback of card orientation.